Defender Paul Boertien is being given a trial at Boundary Park. John Sheridan is hoping that ex-Derby County star will be good enough to fill the troublesome left back position, one of the remaining spots that Shez sees as being in need of strengthening. Boertien has linked up with the squad for pre season training and will probably feature in Athletic's first friendly game at Barrow on Friday.The 28 tear old began his career with Carlisle United but then moved to Derby for £250,000 in 1999, making his debut against Chelsea. He made 114 appearances for Derby, scoring two goals. Boertien also had loan spells at Crewe Alexandra, Notts County and Chesterfield and is now a free agent after being released by Derby at the end of last season.